Function TcpInput

NetworkPkg/TcpDxe/TcpInput.c:744–1628

Process the received TCP segments. @param[in] Nbuf Buffer that contains received a TCP segment without an IP header. @param[in] Src Source address of the segment, or the peer's IP address. @param[in] Dst Destination address of the segment, or the local end's IP address. @param[in] Version IP_VERSION_4 indicates IP4 stack. IP_VERSION_6 indica

**/
INTN
TcpInput (
  IN NET_BUF         *Nbuf,
  IN EFI_IP_ADDRESS  *Src,
  IN EFI_IP_ADDRESS  *Dst,
  IN UINT8           Version
  )
{
  TCP_CB      *Tcb;
  TCP_CB      *Parent;
  TCP_OPTION  Option;
  TCP_HEAD    *Head;
  INT32       Len;
  TCP_SEG     *Seg;
  TCP_SEQNO   Right;
  TCP_SEQNO   Urg;
  UINT16      Checksum;
  INT32       Usable;

  ASSERT ((Version == IP_VERSION_4) || (Version == IP_VERSION_6));

  NET_CHECK_SIGNATURE (Nbuf, NET_BUF_SIGNATURE);

  Parent  = NULL;
  Tcb     = NULL;

  Head    = (TCP_HEAD *) NetbufGetByte (Nbuf, 0, NULL);
  ASSERT (Head != NULL);

  if (Nbuf->TotalSize < sizeof (TCP_HEAD)) {
    DEBUG ((EFI_D_NET, "TcpInput: received a malformed packet\n"));
    goto DISCARD;
  }

  Len     = Nbuf->TotalSize - (Head->HeadLen << 2);

  if ((Head->HeadLen < 5) || (Len < 0)) {

    DEBUG ((EFI_D_NET, "TcpInput: received a malformed packet\n"));

    goto DISCARD;
  }

  if (Version == IP_VERSION_4) {
    Checksum = NetPseudoHeadChecksum (Src->Addr[0], Dst->Addr[0], 6, 0);
  } else {
    Checksum = NetIp6PseudoHeadChecksum (&Src->v6, &Dst->v6, 6, 0);
  }

  Checksum = TcpChecksum (Nbuf, Checksum);

  if (Checksum != 0) {
    DEBUG ((EFI_D_ERROR, "TcpInput: received a checksum error packet\n"));
    goto DISCARD;
  }

  if (TCP_FLG_ON (Head->Flag, TCP_FLG_SYN)) {
    Len++;